1. Field of the Invention
This invention relates to a spindle control command method, and more particularly, to a spindle control command method in which a control of a plurality of spindles is switched by a program command.
2. Description of the Related Art
To carry out machining of workpieces at a high speed, CNC lathes with a plurality of spindles are widely used. In these CNC lathes, opposed spindles may be used to individually machine respective workpieces, or when a long workpiece is to be machined, may be used to cooperatively rotate the workpiece.
Accordingly, it is necessary to provide rotation commands for controlling the two spindles independently as well as those for controlling the spindles as a unit, and to this end, the rotation commands supplied to spindle control circuits are switched by hardware. This switching, however, requires a circuit having a complicated structure and entails an increase in the number of parts required.